An investigation of particle collection efficiency in different particle-bubble contacting environments in flotation

The collection efficiency of quartz particles in four different particle-bubble contacting environments was investigated during this thesis. Flotation experiments were carried out in a hybrid flotation column that could be modified into three different cell configurations (a quiescent column cell, an agitated column cell and a Jameson-type cell), while the fourth cell environment comprised a laboratory batch subaeration flotation cell. High purity quartz was used as a probe ore in conjunction with a cationic collector and a commercial frother blend. The quartz was initially contaminated with organic material and needed to be cleaned by calcination. The cleaned quartz was divided into four narrow particle size fractions to determine the effect of particle size on particle collection efficiency. The quartz was floated over a wide range of collector dosages and frother dosage was kept constant during experiments. The flotation was conducted using tap water at neutral pH. Froth depth was kept shallow during all experiments in the hybrid column cell configurations to enable the investigation to focus specifically on the collection zone. The effect of contacting environment (cell type) on particle collection efficiency was investigated by considering the effect of particle hydrophobicity, particle size and agitation speed (turbulence) on flotation recovery in the different cell types. The unique particle-bubble contacting environments resulted in different particle collection efficiencies and it was found that increased contacting intensity generally led to increased efficiency of collection. Increased particle hydrophobicity generally resulted in increased particle collection efficiency, although the overdosing of collector led to decreased flotation recovery which was probably caused by combined collector double layer and flocculation effects. The effect of particle size on flotation recovery exhibited classical n-curve behaviour at intermediate collector dosages and the optimum particle size range as reported in the literature was confirmed. Intense contacting between particles and bubbles followed by relatively quiescent disengagement (such as the mechanism employed in the Jameson cell configuration) proved to be beneficial to collection of both fine and coarse particles.

Grantor dc:publisher.institution

Department of Chemical Engineering

Year dc:date.issued

1995

Author dc:creator

• Breytenbach, Jacobus Nicolaas

Advisors dc:contributor.advisor

• Franzidis, Jean-Paul
• Harris, Martin
• O'Connor, Cyril

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/11427/20457

OAI identifier oai:identifier

oai:open.uct.ac.za:11427/20457